Pannier Lab
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Hydrogels for Porcine Embryo Culture

Sophie Walsh; collaborator: Jeremy Miles
Albert holding gel

In vitro model for the development of pre-implantation porcine embryos using alginate hydrogels:

Between Day 10 and 12 of gestation in the pig, the embryo transforms from a spherical structure (~1-2 mm) to a long, thin filament (>100 mm) in a process referred to as elongation. Deficiencies in elongation contribute to approximately 20% of embryonic loss, but physiological mechanisms that regulate elongation remain poorly understood. An effective in vitro culture system that can support pig embryo elongation is necessary for evaluating these specific mechanisms of elongation and understanding how these factors are altered during embryonic loss. We hypothesize that previous failure of pig embryos to elongate in vitro is, at least to an extent, due to inadequate culture systems lacking three-dimensional (3-D) structure for maintenance of proper embryo architecture during elongation.

Therefore, we have developed a culture system employing alginate hydrogels as a 3-D matrix that can facilitate embryonic morphological changes with corresponding increases in estrogen production and steroidogenic transcript expression, in a similar pattern as in vivo elongation. Our current project objective is to use this system as an in vitro tool for evaluating biomechanical and uterine factors that promote elongation. Knowledge of these mechanisms that regulate elongation can then be used to develop strategies to improve pregnancy outcomes in the pig and potentially other domestic agricultural species.

In vitro culture model of growth plate cartilage using alginate hydrogels:

Physical damage or congenital disorders that disrupt growth plate cartilage result in skeletal abnormalities that are often associated with long-term intensive health care needs due to impact on the joints, the central nervous system, and the ocular system. Studying the generation of growth plate architecture in vitro is critical for understanding mechanisms that regulate normal development of growth plate cartilage and how these mechanisms are altered in abnormal growth plates. Although significant advances have been made in discovering signal pathways and signaling gradients that regulate growth plate function, it is unclear whether these factors alone are sufficient to induce normal growth plate structure and function, as current methods for in vitro culture of naïve chondrocytes do not generate native cartilage architecture.

We propose that a three-dimensional matrix with appropriate biomechanics, extracellular matrix factors, and signaling gradients will establish an efficient in vitro model of native growth plate cartilage. Specifically, our objective is to determine the extracellular factors required to induce columnar formation of proliferating growth plate chondrocytes in vitro within an alginate hydrogel by investigating the effects of hydrogel biomechanics, integrated extracellular factors, and mechanical/chemical gradients.

Results from this study will extend our understanding of optimal growth conditions for producing tissue that mimics native growth plate cartilage, which is crucial for the development of successful tissue engineered constructs to replace damaged or diseased cartilage.